[FIX] bug of file import related to api.multi

attachment_metadata/models/attachment.py

@@ -33,9 +33,12 @@ class IrAttachmentMetadata(models.Model):
 
     @api.depends('datas', 'external_hash')
     def _compute_hash(self):
-        if self.datas:
-            self.internal_hash = hashlib.md5(b64decode(self.datas)).hexdigest()
-        if self.external_hash and self.internal_hash != self.external_hash:
+        for attachment in self:
+            if attachment.datas:
+                attachment.internal_hash = hashlib.md5(
+                    b64decode(self.datas)).hexdigest()
+            if attachment.external_hash and\
+               attachment.internal_hash != attachment.external_hash:
                 raise UserError(
                     _("File corrupted: Something was wrong with "
                       "the retrieved file, please relaunch the task."))